NCT fail on emissions, will dipetane fix it?

V.W.L 11

jim-mcdee wrote: »

Its one of those "seems to work for some people/cars"

If it really worked as claimed, it would work in every car, every time.

I think it has a placebo effect on people, and the stuff actually does f all.

Did nothing for me anyway, and I gave it a proper try out.

with my readings am i better off changing the cat i wonder,it needs a major service also to be fair

visual

New air filter will help along with new plugs oil filter and oil is your starting point.

Its hard to know about CAT you probably need to replace it but using CAT cleaner might work.

Are you burning oil ? Is there any fault codes ?
something is causing the plugs to be black
Its either too rich or burning oil.

Does the car run up to temperature ?

jimgoose

jim-mcdee wrote: »

Its one of those "seems to work for some people/cars"...

That's the deal with Dipetane/Redex/BG44K/insert-injector-cleaner-of-choice - if you have an issue with carbon deposits and/or fouled injectors, you'll get benefit from them, and if not, as is in fairness more likely to be the case, you won't.

djimi

jim-mcdee wrote: »

I think it has a placebo effect on people, and the stuff actually does f all.

The general advice will be along the lines of a dose of Dipetane and an Italian tune-up; the latter of which Im sure does the majority of the benefit!

V.W.L 11

djimi wrote: »

The general advice will be along the lines of a dose of Dipetane and an Italian tune-up; the latter of which Im sure does the majority of the benefit!

i'm going to give it a full service this week,a fill bottle of dipetane and an itslian tune up,failing all of that a new cat is in order

V.W.L 11

visual wrote: »

New air filter will help along with new plugs oil filter and oil is your starting point.

Its hard to know about CAT you probably need to replace it but using CAT cleaner might work.

Are you burning oil ? Is there any fault codes ?
something is causing the plugs to be black
Its either too rich or burning oil.

Does the car run up to temperature ?

car running up to temperature,plugs and oil are black,its not burning oil (yet) i'm hoping the major service will sort it along with avlitre of fipetane and the italisn tune up,i really have no idea if the cat is gone

Chimaera

Soot means it's running too rich. So it's getting too much fuel or not enough air. Can you post the test results (all of the emissions ones)?

Definitely do a full service: plugs, oil, oil filter, air filter. Make sure to set the gaps on the spark plugs properly.

After that there a bunch of possibilities, but it's probably premature to discuss them without knowing how it failed.

V.W.L 11

Chimaera wrote: »

Soot means it's running too rich. So it's getting too much fuel or not enough air. Can you post the test results (all of the emissions ones)?

Definitely do a full service: plugs, oil, oil filter, air filter. Make sure to set the gaps on the spark plugs properly.

After that there a bunch of possibilities, but it's probably premature to discuss them without knowing how it failed.

it only failed on the high idle,low idle was fine and lambda also passed,the readings were:

CO 1.92% Vol above 0.30 fail
HC 757ppm above 200ppm
Lambda 1.01 between 0.97 & 1.03 pass

those were the only failures,upon opening up the.air filter,oil and oil filter and spark plugs lets just say the colour shocked me,but there was no burning of oil,no misfire,so i hope that with the service and a litre of dipetane and italian tune up i can cure it,engine oil temperature was 81 degrees,the test was at 8.30 last saturday and i drove the car to the test centre which is a 7-8 minute drive from my house so the engine was maybe not as warm as i would have liked.

jca

V.W.L 11 wrote: »

it only failed on the high idle,low idle was fine and lambda also passed,the readings were:

CO 1.92% Vol above 0.30 fail
HC 757ppm above 200ppm

those were the only failures,upon opening up the.air filter,oil and oil filter and spark plugs lets just say the colour shocked me,but there was no burning of oil,no misfire,so i hope that with the service and a litre of dipetane and italian tune up i can cure it

Don't bother with the snake oil. Just do the full service and give it a good long high speed drive.

V.W.L 11

jca wrote: »

Don't bother with the snake oil. Just do the full service and give it a good long high speed drive.

greasepalm recommends cataclean,where in gods name could i get that?is that also snake oil?

jimgoose

V.W.L 11 wrote: »

greasepalm recommends cataclean,where in gods name could i get that?is that also snake oil?

Dummind that. If you insist on a course of injector cleaner, get BG44K. It is a completely serious product that does what it says on the tin. Personally I think your cat is horlicksed.

Chimaera

V.W.L 11 wrote: »

it only failed on the high idle,low idle was fine and lambda also passed,the readings were:

CO 1.92% Vol above 0.30 fail
HC 757ppm above 200ppm
Lambda 1.01 between 0.97 & 1.03 pass

those were the only failures,upon opening up the.air filter,oil and oil filter and spark plugs lets just say the colour shocked me,but there was no burning of oil,no misfire,so i hope that with the service and a litre of dipetane and italian tune up i can cure it,engine oil temperature was 81 degrees,the test was at 8.30 last saturday and i drove the car to the test centre which is a 7-8 minute drive from my house so the engine was maybe not as warm as i would have liked.

Those results point towards very rich running. Given that the lambda reading is ok, it might just be badly in need of a service. Make sure you've driven for about 15-20 minutes before doing the Italian tuneup to make sure the car is up to operating temperature first.

Once you're warmed up, do a pull in 3rd from 2000 rpm up to the redline a few times - ideally on the motorway. On test day, make sure you take it for a good 20 minute drive before the test.

V.W.L 11

jimgoose wrote: »

Dummind that. If you insist on a course of injector cleaner, get BG44K. It is a completely serious product that does what it says on the tin. Personally I think your cat is horlicksed.

i'll service it and stick something in the tank then an italian tune up,after that i'll get the emissions tested in a garage and take it from there

V.W.L 11

Chimaera wrote: »

Those results point towards very rich running. Given that the lambda reading is ok, it might just be badly in need of a service. Make sure you've driven for about 15-20 minutes before doing the Italian tuneup to make sure the car is up to operating temperature first.

Once you're warmed up, do a pull in 3rd from 2000 rpm up to the redline a few times - ideally on the motorway. On test day, make sure you take it for a good 20 minute drive before the test.

would the lambda be gone if the cat was no more good???i'll post pictures of the old spark plugs and oil later on today so you can see exactly what i am seeing

Chimaera

The lambda sensor is mounted before the catalytic converter. It measures the amount of oxygen remaining in the exhaust to determine how well the fuel is combusting. It's what the engine uses to control mixture strength. Your reading is normal so it's not a significant worry.

Taking another look at your results, you have high CO and high HC. This points to incomplete combustion: not all the fuel is burning, and what is burning is not burning well enough. The black plugs and oil corroborate this (soot). The most likely culprit for this in a petrol engine is bad plugs - poor spark means the fuel doesn't light up on time. Your service should fix a lot of this. Throwing in a good fuel additive before the Italian tuneup will help clear out a lot of the soot that's probably built up in there.

A dead cat would show high CO readings but HC readings in the normal range.

V.W.L 11

Chimaera wrote: »

The lambda sensor is mounted before the catalytic converter. It measures the amount of oxygen remaining in the exhaust to determine how well the fuel is combusting. It's what the engine uses to control mixture strength. Your reading is normal so it's not a significant worry.

Taking another look at your results, you have high CO and high HC. This points to incomplete combustion: not all the fuel is burning, and what is burning is not burning well enough. The black plugs and oil corroborate this (soot). The most likely culprit for this in a petrol engine is bad plugs - poor spark means the fuel doesn't light up on time. Your service should fix a lot of this. Throwing in a good fuel additive before the Italian tuneup will help clear out a lot of the soot that's probably built up in there.

A dead cat would show high CO readings but HC readings in the normal range.

i was given a replacement lambda sensor also as a precaution,so by those readings the cat is alive???yeah the state of the plugs would go hand in hand with what you are saying,the oil is like liquid tar

V.W.L 11

spark plug from the bora post nct,not the greatest of pictures but it may give an indication

V.W.L 11

just drained

samih

Chimaera wrote: »

Those results point towards very rich running. Given that the lambda reading is ok, it might just be badly in need of a service.

The lambda is actually 1.01 i.e. slightly lean so it is not running rich. OP, your car suffers from very incomplete combustion for some reason so service is sound advice. New cat definitely won't fix the emissions. I'd start from ignition system and engine timing. Did the car have e.g. a new timing belt between this and the last NCT?

V.W.L 11

samih wrote: »

The lambda is actually 1.01 i.e. slightly lean so it is not running rich. OP, your car suffers from very incomplete combustion for some reason so service is sound advice. New cat definitely won't fix the emissions. I'd start from ignition system and engine timing. Did the car have e.g. a new timing belt between this and the last NCT?

there is 145k on it,belt was changed at 138k,the car is not misfiring or anything

Chimaera

samih wrote: »

The lambda is actually 1.01 i.e. slightly lean so it is not running rich. OP, your car suffers from very incomplete combustion for some reason so service is sound advice. New cat definitely won't fix the emissions. I'd start from ignition system and engine timing. Did the car have e.g. a new timing belt between this and the last NCT?

Looks like you didn't read the rest of the thread before posting....

samih

Chimaera wrote: »

Looks like you didn't read the rest of the thread before posting....

It wouldn't be the first time. -- Reread the thread and my answer was meant for W.V.L 11. The CO and HC are sky high (incomplete combustion) and the lambda was slighty lean (O2 sensor and management doing their job trying to fight the underlying problem).

The cat may also well be damaged with all the unburnt petrol but even a perfect one can only do so much... A typical non-cat car has a CO of around 1-2 % and HC around 100 ppm which a working cat then takes down to 0.1 % and 10 ppm or better.

W.V.L 11: As your timing belt was changed so recently could it be the correct timing tools were not used?

Kenny Logins

jim-mcdee wrote: »

I think it has a placebo effect on people, and the stuff actually does f all.

So if you can employ any other method convincing yourself that your car will pass emissions, it will?

V.W.L 11

samih wrote: »

It wouldn't be the first time. -- Reread the thread and my answer was meant for W.V.L 11. The CO and HC are sky high (incomplete combustion) and the lambda was slighty lean (O2 sensor and management doing their job trying to fight the underlying problem).

The cat may also well be damaged with all the unburnt petrol but even a perfect one can only do so much... A typical non-cat car has a CO of around 1-2 % and HC around 100 ppm which a working cat then takes down to 0.1 % and 10 ppm or better.

W.V.L 11: As your timing belt was changed so recently could it be the correct timing tools were not used?

the belt was changed before i bought it,i done a major engine service this week and it does seem to run much much better,photos of spark plugs and oil on this thread

jca

V.W.L 11 wrote: »

the belt was changed before i bought it,i done a major engine service this week and it does seem to run much much better,photos of spark plugs and oil on this thread

It should pass easily now.

V.W.L 11

jca wrote: »

It should pass easily now.

i'll throw in a litre of dipetane for luck

jca

V.W.L 11 wrote: »

i'll throw in a litre of dipetane for luck

I wouldn't waste me hard earned bobs tbh..

V.W.L 11

jca wrote: »

I wouldn't waste me hard earned bobs tbh..

conflicting reports on the stuff then??!

jca

All your engine needed was a good service, not snake oil.

V.W.L 11

jca wrote: »

All your engine needed was a good service, not snake oil.

hopefully that proves to be the case on the retest